1. Field of the Invention
The invention relates to a robot hand. In particular, the invention relates a robot hand adapted for handling a workpiece heated to a high temperature in a high-temperature area.
2. Description of the Related Art
Conventionally, workpieces that are processed by a processing machine or machines may be held by a hand of a robot and taken out of the processing machine(s). Japanese Laid-Open Patent Publication No. 2010-005732 discloses a robot hand adapted for handling of a workpiece by opening and closing of a holding unit. Japanese Laid-Open Patent Publication No. 2010-149224 discloses another robot hand adapted for handling of a workpiece using an air-actuated adsorption unit.
Furthermore, Japanese Patent Application No. 2011-083685 discloses a servo hand featuring a double-shaft configuration in which in a first shaft with a first nail is coaxially, provided a second shaft with a second nail. The servo hand is thus adapted to change rotational positions of the first and second nails about an axis of the first and second shafts and thereby hold and release the workpiece.
A workpiece may be heated considerably as a result of being processed by specific processing machines such as press machines and forging machines. In the robot hand disclosed in Japanese Laid-Open Patent Publication No. 2010-005732, the servo motor is arranged near the holding unit. Accordingly, when the workpiece is to be taken out of the above-mentioned specific processing machine, or when the workpiece is highly heated, the servo motor is thermally affected, which may cause its lifetime to be degraded. In addition, since the air-actuated adsorption unit disclosed in Japanese Laid-Open Patent Publication No. 2010-149224 has a low heat resistance, it is difficult to use this adsorption unit in a high-temperature environment.
In Japanese Patent Application No. 2011-083685, the servo motor is allowed to be spaced away from the first and second nails at a distance defined by the lengths of the first and second shafts. Accordingly, it is possible to prevent the servo motor from being thermally affected even when the workpiece is at a high temperature.
However, in such a double-shaft configuration in the context of the servo hand described in Japanese Patent Application No. 2010-03685, a bearing provided between the first shaft and the second shaft needs to be placed at the distal end of the servo hand. Consequently, when the servo hand of Japanese Patent Application No. 2010-083685 is moved into the high-temperature area, the bearing may deteriorate due to the thermal effects within the area.
It is therefore an object of the invention, which has been made in view of the foregoing issues, to provide a robot hand capable of handling a workpiece without malfunctioning even in a high-temperature area.